Soil Bacteria Unlock Iron and Potassium for Plants

Background: Potassium (K) and iron (Fe) are vital to plant nutrition. Both nutrients are abundant in soil but in forms that cannot be utilized by plants. For example 98 percent of soil potassium is locked in silicate minerals like mica feldspar and clay. Finding a way to release these nutrients and make them available to plants would be extremely valuable. The iron fertilizers currently on the market are unsatisfactory while the most common potassium fertilizer (KCl or “potash”) doubled in price in the last decade due to global shortage. Technology Description: UW–Madison researchers have developed a method of using common soil bacteria to release iron and potassium in forms suitable for plants. The bacteria are capable of oxidizing the Fe(II) found in silicate minerals. Oxidizing Fe(II) releases iron and potassium that can be absorbed by plants. Suitable bacteria include natural and genetically modified strains of Bradyrhizobia Cupriavidus necator Ralstonia solanacearum Dechloromonas agitate and Nocardioides. One of these Bradyrhizobia is a well-known microorganism used to increase nitrogen bioavailability. Applications: Fertilizer to increase iron and potassium plant nutrition Opportunity for collaboration: The Wisconsin Alumni Research Foundation (WARF) is seeking commercial partners interested in using Fe(II)-oxidizing bacteria to boost the amount of soil iron and potassium available to plants.


1) Unlocks the nutrient potential of soil minerals. 2) A single microorganism (Bradyrhizobia) could be used to enhance levels of iron potassium and nitrogen in soil. 3) Long-term solution to fertilizer shortage concerns.

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